North Korea should be again listed as a state sponsor of terrorism, according to Sen. Ted Cruz, R-Texas.

A sanctions bill against Iran, Russia, and North Korea requires the secretary of state to decide within 90 days whether to relist North Korea, legislation that Cruz introduced, the senator said in a Sunday New York Times opinion piece.

"Americans could be forgiven for wondering why North Korea is not already designated as a sponsor of terrorism," Cruz wrote, and noted that the country was on the list until the U.S. elected to remove it in 2008.

Being designated a terrorism sponsor is a formal indication that diplomatic relations hinge on a country stopping any financing or support for terrorism, Cruz wrote in his opinion piece.

"It is time to acknowledge that North Korea may never be interested in negotiating away its nuclear deterrent," Cruz wrote. "Will we continue our diplomatic overtures to the Kim regime on the flawed assumption that it is interested in a future without nuclear weapons?"

"We must seriously consider the possibility that the North's current leader, Kim Jong-un, is preparing to use nuclear weapons to drive American forces out of South Korea," in order to reunify the Korean Peninsula under North Korean terms, Cruz wrote.

Putting North Korea back on the list "strengthens our hand and weakens that of Kim Jong-un," Cruz wrote in his opinion piece in The Times.